Troubleshooting Low Voltage on Brake Magnets

Question:

So Im only getting 7.5v to my brake magnets. I ran a wire straight from my 7 pin connection for both my ground and power from my brake controller at the vehicle 7 pin connection to eliminate any kind of ground or power loss through the trailer. I am getting 12v with the brakes turned all the way up to ten but when I hook the ground wires up for my magnets it drops down to 7.5v. What am I missing? I dont have a ground problem nor power problem to the magnets what could be causing this power loss? Its on all four brakes so it cant be a bad magnet.

asked by: Alexander W

Expert Reply:

You've either got a bad ground connection or one of your brake magnets are shot. Even if you have new brake magnets, it doesn't mean you have an excellent ground connection, and sometimes the magnets can be faulty.

If you have rechecked your ground connection point and all the wiring looks good and you have a solid connection to bare metal (even some paint can contribute to a bad ground) then I recommend testing each brake magnet individually with a multimeter # PT89ZR. Since they are all daisy-chained together it's possible that only one of them is faulty but it is causing problems on the whole system.

I have attached some helpful articles on trailer wiring and testing your brake magnets that you can reference. These go into a lot more detail and give you step by step instructions on what to look for.

expert reply by: Jon G